常用SQL语句格式积累(四)
名称,[100-85],[85-70],[70-60],[ <60]
SELECT SC.C# as 课程ID,Cname
as 课程名称
,SUM(CASEWHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100- 85]
,SUM(CASEWHEN score BETWEEN 70 AND 85 THEN 1 ELSE 0 END) AS [85 -70]
,SUM(CASEWHEN score BETWEEN 60 AND 70 THEN 1 ELSE 0 END) AS [70 -60]
,SUM(CASEWHEN score < 60 THEN 1 ELSE 0 END) AS [60-]
FROM SC,Coursewhere SC.C#=Course.C#
GROUP BY SC.C#,Cname;
24、查询学生平均成绩及其名次
SELECT 1+(SELECTCOUNT( distinct 平均成绩)
FROM(SELECT S#,AVG(score) AS 平均成绩
FROM SC
GROUP BY S#
) AS T1
WHERE平均成绩 > T2.平均成绩) as 名次,
S# as 学生学号,平均成绩
FROM (SELECT S#,AVG(score) 平均成绩
FROMSC
GROUP BY S#
) AS T2
ORDER BY 平均成绩 desc;
25、查询各科成绩前三名的记录:(不考虑成绩并列情况)
SELECT t1.S# as 学生ID,t1.C#as 课程ID,Score as 分数
FROM SC t1
WHERE score IN (SELECT TOP 3score
FROMSC
WHEREt1.C#= C# ORDER BY score DESC
)
ORDER BY t1.C#;
26、查询每门课程被选修的学生数
select
c#,count(S#) from sc group by C#;
27、查询出只选修了一门课程的全部学生的学号和姓名
select SC.S#,Student.Sname,count(C#) AS 选课数
from SC ,Student
where SC.S#=Student.S# group bySC.S# ,Student.Sname having count(C#)=1;
28、查询男生、女生人数
Select count(Ssex) as 男生人数 fromStudent group by Ssex having Ssex='男';
Select count(Ssex) as 女生人数 fromStudent group by Ssex having Ssex='女'；
29、查询姓“张”的学生名单
SELECT Sname FROM Student WHERESname like '张%';
30、查询同名同性学生名单，并统计同名人数
select Sname,count(*) fromStudentgroup by Sname having count(*)>1;;
31、1981年出生的学生名单(注：Student表中Sage列的类型是datetime)
select Sname, CONVERT(char(11),DATEPART(year,Sage)) as age
from student
where CONVERT(char(11),DATEPART(year,Sage))='1981';
32、查询每门课程的平均成绩，结果按平均成绩升序排列，平均成绩相同时，按课程号降序排列
Select C#,Avg(score) from SC groupby C# order by Avg(score),C# DESC ;
33、查询平均成绩大于85的所有学生的学号、姓名和平均成绩
select Sname,SC.S# ,avg(score)
from Student,SC
where Student.S#=SC.S# groupby SC.S#,Sname having avg(score)>85;
34、查询课程名称为“数据库”，且分数低于60的学生姓名和分数
Select Sname,isnull(score,0)
from Student,SC,Course
where SC.S#=Student.S# and SC.C#=Course.C#and Course.Cname='数据库'and score <60;
35、查询所有学生的选课情况；
SELECT SC.S#,SC.C#,Sname,Cname
FROM SC,Student,Course
where SC.S#=Student.S# and SC.C#=Course.C#;
36、查询任何一门课程成绩在70分以上的姓名、课程名称和分数；
SELECT distinctstudent.S#,student.Sname,SC.C#,SC.score
FROM student,Sc
WHERE SC.score>=70 AND SC.S#=student.S#;
37、查询不及格的课程，并按课程号从大到小排列
select c# from sc where scor e <60 order by C# ;
38、查询课程编号为003且课程成绩在80分以上的学生的学号和姓名；
select SC.S#,Student.Sname from SC,Student whereSC.S#=Student.S# and Score>80 and C#='003';
39、求选了课程的学生人数
select count(*) from sc;
40、查询选修“叶平”老师所授课程的学生中，成绩最高的学生姓名及其成绩
select Student.Sname,score
from Student,SC,Course C,Teacher
where Student.S#=SC.S# andSC.C#=C.C# and
C.T#=Teacher.T#and Teacher.Tname='叶平' andSC.score=(select max(score)from SC whereC#=C.C# );
41、查询各个课程及相应的选修人数
select count(*) from sc group by C#;
42、查询不同课程成绩相同的学生的学号、课程号、学生成绩
select distinct A.S#,B.score from SC A ,SC B where A.Score=B.Score and A.C# <>B.C# ;
43、查询每门功成绩最好的前两名
SELECT t1.S# as 学生ID,t1.C#as 课程ID,